The MPI, which is based on a quarterly survey of multifamily builders and developers, tracks sentiment about construction of new apartments on a scale of 0 to 100.The MPI increased from 44.4 in the second quarter to 47.3 in the third quarter—the highest reading since the fourth quarter of 2005.

The MPI measures construction in low-rent apartments, market-rate rental apartments and “for-sale” units, or condominiums. Any number over 50 indicates that more respondents report conditions are improving than report conditions are getting worse.

Derived from the same NAHB survey, the Multifamily Vacancy Index (MVI) measures property owners’ perception of vacancies in existing rental apartments. The MVI decreased from 36.1 in the second quarter to 35.1 in the third quarter. With the MVI, lower numbers indicate fewer vacancies. The MVI has improved considerably since reaching a peak of 70.2 in the second quarter of 2009.